Update and simplification of the variables names and definitions
for heat sources and heat flux. A new section about heat fluxes is
available in the documentation.

Incident Intensity boundary
condition can be defined using the discrete directions used by the
discrete ordinate method.

Wall boundary condition in
Heat Transfer in Participating Media has
been renamed to Opaque Surface
boundary condition. In version 4.2 it accounts for the thermal
contribution of the net radiative heat flux.

Backward Compatibility vs. 4.1

Wall Features in Radiation in Participating Media

The Wall (wall) feature in the Radiation in Participating
Media interface has been renamed Opaque Surface (os) in version
4.2. Model Java-files or Model M-files that create and solve COMSOL
models containing Wall features need to be updated to use Opaque Surface
instead. When the Opaque Surface is used in the Heat Transfer interface
in version 4.2, it adds a new heat flux term that is equal to qw,
which is the net radiative heat flux. If you do not want to keep this
term in an imported model from version 4.1, you must add a Heat Flux
feature on the same selection as the Opaque Surface, and the parameter q0
must be set to -id.qw, where id
is the physics interface identifier.

Backward Compatibility vs. 3.5a

k-ω Turbulence Model

The k-ω turbulence model
physics interface is not yet implemented in version 4.2. It is planned
for the CFD Module in version 4.2a.

Version 4.1 includes automatic translation of models built with the
previous k-ω turbulence model. When
opened, the full model, including initial values and boundary
conditions, is converted to the k-ε
turbulence model. Once opened, the model can also be also be changed to
the Low-Reynolds k-e Turbulence Model interface. The latter
physics interface presents an excellent alternative for higher accuracy
in models including confined flows.

Momentum transport Wall Functions are translated into the revised
Wall Functions in 4.2. The Heat equation Wall Functions are also
translated, but the translated formulation uses the default turbulence
modeling constants, regardless of the values that were defined in Physics>Scalar Variables in 3.5a.